install.sh fails with BASH_SOURCE[0] unbound variable error

[lay-g]

Bug Description

Running the install script fails with the following error:

$ curl -fsSL https://raw.githubusercontent.com/guard22/opencode-tps-meter/main/install.sh | bash
bash: line 12: BASH_SOURCE[0]: unbound variable
bash: line 12: cd: null directory

Steps to Reproduce

1. Run: curl -fsSL https://raw.githubusercontent.com/guard22/opencode-tps-meter/main/install.sh | bash

Environment

Name	Value
OS	macOS 26.3.1 (a)
Shell	/bin/zsh 5.9 (arm64-apple-darwin25.0)
OpenCode	v1.3.13